This exercise will help you build your
speed, and it is also a generic blues
bass line.  It sounds very similar to
the "Woo Hoo" song on the Vonage 
commercial, by the 5—6—7—8's.

G—————————————————————————————————
D———————5—6—5———————————5—6—5—————
A———5—8———————8—5———5—8———————8—5—
E—6———————————————6———————————————
  M I P I M I P M — The fingers 
                   you should use

G———————5—6—5—————————————————————
D———5—8———————8—5———————5—6—5—————
A—6—————————————————5—8———————8—5—
E—————————————————6———————————————

G————————7—8—7————————————5—6—5—————
D———7—10———————10—7———5—8———————8———
A—8—————————————————6—————————————5—
E———————————————————————————————————

G—————————————————————————————————
D———————5—6—5—————————————————————
A———5—8———————8—5—————————————————
E—6———————————————6—6—6—6—6—6—6—6—

A great thing about this exercise is that
you can move it anywhere on the fretboard,
and it will give you practice with bigger 
and smaller frets.

One more thing: If you are playing this as
a blues bass line, or if you're just done 
practicing it, there is an alternative,
very bluesy ending:

G———————————————————————————————————————
D———————5—6—5——————————————5—7—8————————
A———5—8———————8—5——5—6—7—8——————————————
E—6———————————————6—————————————————————

Enjoy, and good luck!